<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        ul{
            list-style-type: none;
            height: 70px;
            width: 202px;
            overflow: hidden;
            transition: linear 2s;
            float: left;
        }
        li{
            margin-top: 10px;
            width: 200px;
            height: 50px;
            line-height: 50px;
            text-align: center;
            border: 1px solid red;
        }
        ul:hover{
            height: 600px;
        }
    </style>
</head>
<body>
    <ul>
        <li class="lis">水果列表</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
    </ul>
    <ul>
        <li class="lis">水果列表</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
    </ul>
    <ul>
        <li class="lis">水果列表</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
        <li class="li">苹果</li>
    </ul>
</body>
</html>